Background: Mental health research on Operation Enduring Freedom/Operation Iraqi Freedom/Operation New Dawn (OEF/OIF/OND) Veterans in VHA care highlights the high prevalence of posttraumatic stress disorder (PTSD) among this important population. Although high quality, evidence-based PTSD treatment is available in VHA, and is necessary to help heal these OEF/OIF/OND Veterans with PTSD and to avoid the possibility of chronicity, mental health treatment seeking and utilization is extremely low among those with PTSD. The yearly VHA mandatory PTSD screening program may be an important early identification and treatment access point for OEF/OIF/OND Veterans with PTSD who have not actively sought care for their PTSD symptoms. However, characterizing factors associated with timely treatment initiation and engagement among OEF/OIF/OND patients who are identified with PTSD via the screening program has not been accomplished. Further research is also needed to identify potential ways to increase timely treatment initiation and engagement for all OEF/OIF/OND Veterans with PTSD, to test interventions aimed at enhancing PTSD treatment initiation and engagement, and to understand implementation issues related to maximizing the potential impact of developed interventions. Objectives: The purpose of this project is to provide critical and timely evidence to fill in the existing gaps regarding treatment initiation and engagement among OEF/OIF/OND Veterans with PTSD in VHA. The specific aims of the proposed CDA-2 research are: (1) to identify patient and provider factors associated with timely treatment initiation and continued engagement among all OEF/OIF/OND Veterans in VHA care who receive positive PTSD screens and are diagnosed with PTSD in primary care; (2) further elucidate patient factors associated with timely initiation and continued engagement in PTSD treatment using a qualitative approach with provider and OEF/OIF/OND Veteran patient focus groups; (